Template or tips you recommend for efficient knowledge transfer of an IT support project

Hi smart folks,
What template or tips you recommend when tasked with knowledge transfer within a week or two from a 3rd party who were in charge of a IT support (Software tools plugged to databases, agile based ticket support to resolve issues in using tools, etc). The challenge is to do the best with a week or two available before the team is removed from the project 😦

Thanks.